Remote controlled vacuum brake valve



June 18, 1940. D F, SEARLE 2,204,706

REMUTE CDNTROLLED VACUUM BRAKE VALVE Filed April 24, 19259 #A W0@ 0 o ,Illlllk/3 j INVENTOR. DuDLEY/r" SEARLE BY DTORNEY.

Patented une 18, 1940 UNITED STATES PATENT NOFFICE t accompanying drawing."

" Dudley F. sarleyoakiaiid, Calif.

Application Apri124, 1939,- serialNo; 269,555 claims. (o1. 30s- 31) This invention `relates to vacuum operated brakes particularly for trailer vehicles, and the principal object of the invention is to provide improvements in such apparatus contributing to simplicity, accessibilityand reliability, as well as a construction which will include within a` valve housing .means for 'closing a stop signal light when the vacuum is applied for setting the brakes.

Other features and advantages of the construction will appear in the following description and `In the drawing: The figure is a longitudinal or vertical central sectionalview of one `of my improved remote p controlled vacuum brake valves shown about full size and with the cooperating elements oflthe braking system shown diagrammatically'in operative relation to it.`

In further detail I represents the towing automobileiand 2 the trailer orroad vehicle being towed. 3 is the engine on the towing car, 4 its `intake or suction manifold, and 5 any common type of remote control vacuum valve for `manual operation by the driver of the car by "means of `handle 6.3 f

On the trailer is a storage vacuum tank 1 to provide `suilcient vacuum capacity for `operating `all of the `trailer brakes, 8` is one of the brake actuating or power pistons in its working or `power cylinder 9 which upon exhaustion operates the piston` and applies the brakes (not shown) to an extent depending on the degree of exhausftion applied and maintained by the remote controlled vacuum brake valve generally designated II), and the moment an operative vacuum is induced within the power cylinder 9 the red stop light `II is illuminated. through closure of `its electrical circuit I2 by the movement of parts within the valve structure.` The battery for energizing the stop light circuit is indicated i as carried by the trailer at I3, though it may be on the truck if desired. Y The valve construction comprises a central hollow body I4 closed by av lower cover I5 and an upper cover I6 screwed or bolted around its margins thereto as indicated at I1.` These three body parts are preferably circularin plan, and the lower orbottom cover has a tapped hole at I9 `and a drain cock or plug at I9', while the upper cover I6 has a central hub 20 surrounded by air intake openings 2|, and the hub supports above `it any desired type of air filter 22 to lter outside air drawn through opening2| in direction of the arrows when releasingthe brakes.

the valveare flexible diaphragms 23, 24 preferably of rubber, both being firmly clamped in place by the cover securing screws I1. The lower diaphragm 23 is imperforate, while the upper diaphragm' is provided with a central opening 25 and is made somewhat thicker over its central area as Yat 24,' where it forms an operative seal as will later be explained.4

l'I'he `hollow body portion I4 is provided with a `tapped opening at 26 which connects with a pipe`21 or tube leading from the power cylinder '9,and at the opposite side with a tapped opening28which connects with a pipe 56 leading to storage vacuum tank 1.

Within the hollow body is a circular rim 29 forming an annular space 30 which is open at the left to pipe opening 28, and the circular space 3| within rim`29 is open at one side to pipe opening 26, while suitable partition walls 32, 33, 34, 35 lseparate the spaces mentioned as well as pipe openings 26 and 28 from a central chamber 36, though partition wall 33 is apertured` at 31 to open the central chamber to pipe opening 28.

Horizontal wall 32 carries a central hub 38, and circular rim 29 is preferably tapered to a narrow ridge on top and normally impinges the` under side'of `the thick portion 24' of diaphragm 24 to i form a circular seal thereagainst.

I29,01` between rim 29 and the edge of `opening 25.

4The stem 29 of the disk `valve is sealed against `leakage of air through its guiding hub 38 as by means of a thin iiexible rubber cupped washer 45 resiliently contacting the under side of the disk valve and the upper side of horizontal partition 32 and this washer is preferably further resili- `ently urged to seat air tight against said partition by means` of a light coiled spring 46.

As an upward movement of the disk valve will cause the brakes to be applied, it is biased in a downward direction by a coiled compression .spring 41 reacting between hub 28 and the upper side of the valve disk. i

The ends of circuit wires I2 pass throughinsulating sleeves 48 to central chamber 36 where they are each provided with spring contact terminals 49 adapted to contact with washer 40 to close the stop light circuit when the brakes are applied.

The piping of the elements includes a pipe 50 which includes a flexible hose section 50 extending from tapped opening I8 to the operators valve 5, a pipe 5| from the operators valve 5 to the source of vacuum 4 of the engine, and a pipe 52 which includes a exible hose section 52' from the vacuum tank 'l to pipe 5I or the source of vacuum in advance of the operators valve 5 so that tank 'l is always openl to vacuum though check valved at 53 against admission of air or vapor to the tank when the engine is not running, and also check valved at 53' by a normallyspring opened check valve adapted to close only upon breakage of line 52 but to remain open for operability of valve 5 when check valve- 53 is closed during times when the engine is notV below diaphragm 23 to atmospheric pressure.

My' use of the word vacuum herein and in the claims is of course to be taken in its `ordinarily accepted sense as meaning various degrees of negative pressure below atmospheric,and such terms as increasing, reducing, or releasing aA vacuum etc. are to be understood in their popular sense. n

In operation-@with the arrangement of parts as described and assuming tank l to be under vacuum, and the brakes having been already applied so. that power piston 8 is retracted, diaphragm 2li is sealed against both circular rims 29 and IM, and electric' terminals are closed by disk 40 so that red stop light ll is burning: As long as operating handle iij is not moved the `part'swill all stayin the positions shown, as the power cylinder vacuum is sealed against any change of pressure by diaphragm valve 24 closing ofi any connection rwith vacuum tank l .or air admission ports 2 I.

As there is a high vacuum in chamber 36 which is (under the showing of the drawing) just about counterbalanced by the vacuum in chamber 55 together with the springs, gravity and other forces acting onA the iiat valve member 43, any reduction of the vacuum in 55 by operating valve 5 willk (by reason of the vacuum in chamber 35) lift diaphragm Mi and with it stem 35y and valve 43 to thereby lift diaphragm 24 from rim 29 and thereby open annular` vacuum chamber 30 to pipe 2l and thereby increase the vacuum in the power cylinder 9 and apply the brakes withincreased force, but as the increasing vacuum under central part of the ydiaphragm and flat valve l5 increases the effective outer air pressure to build up to a point Where it forces the valve and diaphragm down again to balance the pressure in chamber 55 and again seal the parts in the position shown in the drawing with the brakes set, under the increased force.

To release the brakes the operating valve handle 5 is moved to draw an increased vacuum in chamber 55 to thereby lower diaphragm 23, and valve disk i3 (due to the relativelyincreased air pressure above it) so that the valve rim 44 Vis out of sealing'contact with the underside of diaphragm 24 and free air rushes 'in through the filter 22 and` openings fil, 25j, chamber 3l and through pipe 21 to power cylinder 9, and thus releases piston 8 so that the usual brake releasing springs can function.

If the vacuum in the power cylinder is only partially reduced by applying a low vacuum to chamber 55, the effective air pressure against the upper surface of the disk Valve and inner portion of diaphragm 24' is also reduced so that the valve rises again to sealing `position against the diaphragmto hold the parts in position shown at such pressure.

When the brakes are entirely released by applying a full vacuum to chamber 55, diaphragm 23 is forced downto break the stop light circuit through plate 4l), and diaphragm 24 seats tightly on rim 29 to seal off vacuum chamber 30 from any connection with the power cylinder. In` case of an accident on the road resulting in the breaking away of the trailer, the fracturing of hose 52 will have no effect on the brakes I Avacuum chamber Sii tochamber 3l and at once applyl fullvaouumftothe power cylinder and' conseq uentlyv lock the brakes under greatest pressure-to stop the trailer and at the Sametime close the stopulightcircuit. Check valve 53 is spring unloaded, that is, remainsopen during regular operation of theapparatusbut will close instantly upon the pressure of the'outside atmosphere being suddenly admitted toit,l as by the breaking` of hose 52", whereascheck valve 53 is spring( loadedv to close while yyielding to the suction of the engine. Thislatter valve will therefore, close when the engine stops running, so as to leave` a working vacuum inthe system,

I am aware of prior remote controlled vacuum valves operating-generally inv thefmannerpdescribed, but believe the construction shown to haveseveral distinct advantages as expressed ,within` the scope of my appended claims.

Iy claim l Y l. In a vacuum brake Valve of the characterdes'cribed,f a hollow body, a first and a second exible diaphragm extending across thebody at opposite ends thereot in sealed relation to the margins of said body, a partition intermediate the diaphragms forming a separate inner chamber ,gp

within said body and closed on one` side by the first diaphragm seated against a rim on said partition, a disk valve positioned within the connes of. said rim arranged to seat at one side yagainst, said rst diaphragm andprovided with vclosed chamber, two separate connections to the `space in said body one open to the space outside of said` partition and the other to the space within said partition, and an. aperture in said rst diaphragm within the area of said disk valve..

2; In` a structure as set out in/claim l, means delivering ltered air through said aperture to said inner chamber when said valve is unseated. 3. In astructure; as set out inclaim 1, means /mQunting air: lter .Straddling thef outer side ,7;5

of said rst diaphragm for delivering air `through said aperture to `said inner chamber when said valve is unseated. l i

4. In a structure as set out in claim 1, said first diaphragm being formed of rubberdike material and of increased thickness over the general area contacted by said rim and said disk valve.

5. In a structure as set out in claim 1, means sealing the stem of said valve against leakage of air therealong While preserving its freedom to slide in supporting means.

DUDLEY F. SEARLE 

